1. Field of the Invention
The present invention relates to a light adjusting apparatus that adjusts light by inserting/removing a light adjusting section into/from an optical path.
2. Description of the Related Art
Image pickup apparatuses having an image pickup function are widely used in various fields, and among them, there is a field of small image pickup apparatuses with a relatively small shape. Examples of such small image pickup apparatuses include electronic endoscopes including a micro video scope, optical microscopes provided with an image pickup function and portable apparatuses provided with an image pickup function.
With conventional small image pickup apparatuses, priority is given to miniaturization, and therefore fixed focus lenses, fixed aperture diaphragms, fixed characteristic filters or the like have been adopted as optical elements such as lenses, diaphragms and optical filters.
In contrast, in recent years, high image quality is also required for such small image pickup apparatuses, and, as optical elements of the aforementioned light adjusting apparatus, there is a growing demand for adopting focus lenses, variable diaphragms, variable characteristic filters or the like, that is, functions as light adjusting apparatuses that adjust light.
Thus, many techniques for downsizing light adjusting apparatuses are being proposed so as to be applicable to small image pickup apparatuses.
As an example, Japanese Patent Application Laid-Open Publication No. 9-22042 describes an electromagnetic drive apparatus disposed around a taking lens, including a yoke, a coil and a permanent magnet facing the yoke, and configured to supply current to the coil to generate a magnetic force in the yoke and rotate the permanent magnet. By providing the permanent magnet with, for example, a shutter blade integrally rotatably as a light adjusting section, it is possible to switch between a state in which the shutter blade is located in an optical path and a state in which the shutter blade is retracted from the optical path.